John d



J. D. HOFF KILN.

APPUCATION FILED DEC- 1,19.

Patented June 24, 1919.

FIG. 1,

JOHN D. HOFF, 0F OAKLAND, CALIFORNIA.

KILN.

Specification of Letters Patent.

Patented June 24, 1919.

Application filed December 1, 1917. Serial No. 204,975.

To all whom it may concern:

Be it known that I, JOHN D. Horn, a citizen of the United States, residing at Oakland, in thecounty of Alameda and State of California, have invented certain new and useful Improvements in Kilns, of which the following is a specification.

The present invention is an improved con tinuous calcining kiln.

The principal object of the invention is to provide a kiln of such construction that ore to be burned may be placed in the top of the kiln and the powdered mass resulting from the firing will gravitate to the bottom and to delivery chutes without interrupting 0r obstructing the flames or feed of the kiln, so that where continuous means of removal are applied the kiln itself will be automatically continuous requiring no attention excepting feed.

This object is fully accomplished in the novel structure described in the following specification and illustrated in the accompanying drawing, in which,

Figure 1 is a vertical side view of my improved kiln, a quarter of same being broken awayto show in section some of the details of construction. The part broken away is indicated in dotted lines 1-1 of Fig. 2.

Fig. 2 is a horizontal section of my kiln on the line 22 of Fig. 1.

Referring to the drawings, 1 indicates a central circular flue surrounded by an inner wall 2 and by an outer wall 3. Between said inner and outer walls are air spaces 4:.

Near the base of the central flue are delivery ports 5 affording access to the bottom of the kiln from the four points of the compass.

The purpose of the ports 12 is to prevent the clogging of the fire chambers 7.

As the ore is reduced to powdered form by the fires it gravitates as shown by the line 13 into the delivery'ports 5. Should the supply exceed the delivery in the ports 5 and the powdered mass assume the size and position shown by the dotted line 14: in Fig. 1, the fire chambers will be kept clear by the ports 12 through which the powdered mass gravitates to the ports 5 and is carried away.

In Fig. 2 I have shown a damper 16 slidable on the floor 11 to adjust the size of ports 12.

What I claim as new and wish to secure by Letters Patent is A continuous calcining kiln comprising a central flue open at the top and provided with a plurality of radially arranged discharge ports at its base, with observation ports, and with firing chambers provided with ports leading to the discharge ports and adapted to conduct any overflow in said fire chambers into the discharge ports below.

In testimony whereof I afiix my signature.

JOHN D. I-IOFF.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, I). 0. 

